Alloys and semi-finished products and products containing same

ABSTRACT

Described includes an alloy consisting of at least 33 wt. % to at most 75.5 wt. % gold, at least 1.5 wt. % to at most 45 wt. % silver, at least 8 wt. % to at most 45 wt. % copper, the remainder being zinc. The invention also relates to a semi-finished product made from such an alloy, a piece of jewelry having at least one such semi-finished product, and a method for producing such a semi-finished product.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of German Patent Application 10 2020 206 620.5, filed May 27, 2020, the content of which is hereby incorporated by reference in its entirety.

SUMMARY

The invention relates to an alloy, in particular to a noble metal alloy, a semi-finished product made from such an alloy, a piece of jewelry having at least one such semi-finished product, and a method for producing such a semi-finished product.

Alloys, in particular noble metal alloys, with a gold content of at least 33 wt. % (mass percent), in particular gold alloys, typically have a high ductility. In particular, they typically react to shear stress with plastic deformation, and they typically break when subjected to increased stress. This limits the use of such alloys, in particular for specific pieces of jewelry that require elastic properties, or makes it seem impossible to produce elastic pieces of jewelry from alloys, in particular noble metal alloys with a gold content of at least 33 wt. %, in particular from gold alloys.

The invention is based on the object of creating an alloy, a semi-finished product made from such an alloy, a piece of jewelry having at least one such semi-finished product, and a method for producing such a semi-finished product, for which the disadvantages mentioned above do not occur.

The object is achieved in that the present technical teaching is provided, in particular the teaching of the independent claims and the embodiments disclosed in the dependent claims and the description.

The object is achieved in particular by creating an alloy consisting of at least 33 wt. % to at most 75.5 wt. % gold, at least 1.5 wt. % to at most 45 wt. % silver, at least 8 wt. % to at most 45 wt. %

copper, the remainder being zinc. It has surprisingly been found that such an alloy makes it possible to produce semi-finished products and in particular pieces of jewelry with elastic properties. It is thus possible to form semi-finished products and pieces of jewelry with elastic properties from gold-containing alloys and, conversely, to use a gold-containing alloy in order to produce elastic, in particular at least elastically deformable, semi-finished products and pieces of jewelry. On the one hand, this expands the range of applications for gold-containing alloys; on the other hand, it becomes possible to produce specific pieces of jewelry with elastic properties from gold or using gold.

In particular, the mass fractions of the individual components specified, including the remainder of zinc, add up to 100 wt. % in the alloy.

In the scope of the technical teaching proposed herein, the wording “remainder of zinc” means in particular that the components of the alloy that are 100 wt. % missing with respect to the constituents of the alloy specified with specific mass percentage ranges or specific mass fractions are formed by a zinc component. According to one embodiment, the zinc component is pure zinc; according to another embodiment, the zinc component comprises zinc having—in particular unavoidable—impurities, in particular traces of impurities.

According to a development of the invention, it is provided that the alloy has a copper content of at least 9 wt. % to at most 42 wt. %, preferably from at least 17 wt. % to at most 27 wt. %.

Preferably, the copper content is at most 40 wt. %, preferably at most 35 wt. %, preferably at most 30 wt. %, preferably at most 25 wt. %, preferably at most 20 wt. %, preferably at least 10 wt. %, preferably at least 15 wt. %, preferably at least 18 wt. %, preferably from at least 16 wt. % to at most 21.5 wt. %, preferably from at least 19 wt. % to at most 21 wt. %, preferably from at least 19.6 wt. %

to at most 20.6 wt. %,

According to a further development of the invention it is provided that the alloy has a silver content from at least 2.5 wt. % to at most 39 wt. %, preferably from at least 3.5 wt. % to at most 27.5 wt. %.

Preferably, the silver content is at most 40 wt. %, preferably at most 35 wt. %, preferably at most 30 wt. %, preferably at most 25 wt. %, preferably at most 20 wt. %, preferably at most 15 wt. %, preferably at most 10 wt. %, preferably at most 5 wt. %, preferably at most 4 wt. %, preferably at least 2 wt. %, preferably at least 3 wt. %, preferably at least 5 wt. %, preferably at least 10 wt. %, preferably at least 15 wt. %, preferably from at least 3.8 wt. % to at most 4.2 wt. %, preferably from at least 3.9 wt. % to at most 4.1 wt. %,

Preferably, the gold content of the alloy is from at least 33.3 wt. % to at most 75.5 wt. %, preferably at least 40 wt. %, preferably at least 45 wt. %, preferably at least 50 wt. %, preferably at least 55 wt. %, preferably at least 60 wt. %, preferably at least 65 wt. %, preferably from at least 70 wt. % to at most 75.3 wt. %, preferably from at least 75 wt. % to at most 75.1 wt. %.

The alloy preferably consists of at least 70 wt. % to at most 75.5 wt. % gold, at least 2.7 wt. % to at most 4.2 wt. % silver, at least 16 wt. % to at most 21.5 wt. % copper, the remainder being zinc.

The alloy preferably consists of at least 75 wt. % to at most 75.1 wt. % gold, at least 3.7 wt. % to at most 4.0 wt. % silver, at least 19 wt. % to at most 21 wt. % copper, the remainder being zinc.

Preferably, the alloy consists of at least 75 wt. % to at most 75.1 wt. % gold, preferably at least 3.1 wt. % to at most 4.0 wt. % silver, preferably at least 19.6 wt. % to 21.6 wt. % copper, the remainder being zinc.

Preferably, the alloy consists of 75 wt. % gold, 4.3 wt. % silver, 20 wt. % copper, the remainder being zinc.

The alloy preferably consists of 75.1 wt. % gold, 4.0 wt. % silver, 20.6 wt. % copper, the remainder being zinc.

The alloy preferably consists of 75.5 wt. % gold, 2.1 wt. % silver, 22 wt. % copper, the remainder being zinc.

Preferably, the alloy consists of 75 wt. % gold, 1.7 wt. % silver, 23 wt. % copper, the remainder being zinc.

The object is also achieved in that a semi-finished product is created which has an alloy according to the invention or an alloy according to any of the embodiments described above. Preferably, the semi-finished product is made from such an alloy. The semi-finished product has the shape of a slotted tube. Such a semi-finished product advantageously has elastic properties, in particular when subjected to stress perpendicular to a longitudinal extension of the slotted tube. Such a semi-finished product in the form of a slotted tube is also referred to as a hinge.

According to a further development of the invention, it is provided that the semi-finished product is formed from a sheet metal elongated in a first direction. This first direction corresponds to a direction of the longest extension of the semi-finished product, in particular the slotted tube, and consequently the longitudinal direction of the slotted tube. The sheet metal is shaped, preferably bent, in a second direction, which is perpendicular to the first direction—with the second direction preferably extending in a plane spanned by a surface of the sheet metal—in a circular shape, in particular a circular segment shape. In particular, the slotted tube is formed in this way. The slot is formed in that the opposite ends of the sheet metal are provided at a finite distance from one another along an imaginary circular line so that the tube does not have a closed circular cross section, but rather a circular segment-shaped cross section that is partially open in the form of the slot. A cross-sectional plane of the semi-finished product is a plane on which the longitudinal direction is perpendicular.

The sheet metal is preferably formed into the shape of a circular ring segment by being drawn, in particular through a round drawing die.

The semi-finished product designed in this way preferably has an outer diameter from at least 0.3 mm to at most 5.0 mm, preferably from at least 0.5 mm to at most 1.5 mm, preferably from 0.9 mm to at most 1.3 mm, preferably from at least 0.99 mm to at most 1.2 mm.

The semi-finished product in the form of the slotted tube preferably has an inside diameter from at least 0.03 mm to at most 4.5 mm, preferably from 0.4 mm to 3 mm, preferably from at least 0.55 mm to at most 0.76 mm.

The smallest distance between the ends of the sheet metal bent towards one another in the region of the slot is preferably from at least 0.02 mm to at most 1.0 mm, preferably from at least 0.04 mm to at most 0.08 mm, preferably 0.06 mm.

A preferred embodiment of the semi-finished product has an outside diameter of 1.2 mm, an inside diameter of 0.76 mm, and the smallest distance in the region of the slot of 0.06 mm

Another preferred embodiment of the semi-finished product has an outside diameter of 0.99 mm, an inside diameter of 0.55 mm, and the smallest distance in the region of the slot of 0.06 mm.

According to a further development of the invention, it is provided that the semi-finished product has a spring constant, in particular measured at a distance of 15 mm from a clamping, in particular when force is applied by means of a pressure piece at a speed of 0.1 mm/s, from at least 1500 N/m to at most 2200 N/m, preferably from at least 1600 N/m to at most 2100 N/m, preferably from at least 1700 N/m to at most 2050 N/m, in particular 1964 N/m for a clamping with an arrangement of the slot pointing toward the acting force, in particular 2025 N/m for a clamping with an arrangement of the slot pointing contrary to the acting force, in particular 1720 N/m for a clamping with an arrangement of the slot aligned perpendicular to the acting force. Corresponding values for the spring constant could in particular be measured in such a semi-finished product, whereby it could be demonstrated that the semi-finished product formed in this way, in particular a semi-finished product produced in the scope of the method defined below, has elastic properties. In particular, it was possible to measure the values specified specifically for specific clampings for a semi-finished product having an alloy consisting of 75.1 wt. % gold, 4.0 wt. % silver, 20.6 wt. %

copper, the remainder being zinc. For a correspondingly clamped sample made of a conventional gold alloy with a gold content of 75 wt. %, a spring constant of 1106 N/m was obtained before curing, and of 1008 N/m after curing. A spring constant of 3958 N/m was obtained for an appropriately clamped spring steel sample. It can thus be seen that the semi-finished product proposed here made of the alloy proposed has a spring constant that is significantly increased in the direction of spring steel compared to a conventional gold alloy.

The object is also achieved in that a piece of jewelry is created which has at least one semi-finished product according to the invention or at least one semi-finished product according to one of the previously described embodiments that is wound at least partially along a longitudinal direction, i.e., along the first direction. In this way, in particular, an elastic piece of jewelry made of a gold-containing alloy or gold alloy can advantageously be provided.

The semi-finished product is thus wound up in particular along the longitudinal direction of the slotted tube.

The semi-finished product is preferably wound up helically along the first direction. It can thus in particular have a helical spring-like appearance.

According to a further development of the invention, it is provided that the piece of jewelry has at least two semi-finished products wound parallel to one another along the respective longitudinal direction, i.e. the first direction. In particular, the semi-finished products are arranged adjacent to one another along their entire extent, i.e. in particular run parallel to one another along the helical winding. The piece of jewelry thus preferably has a helical multiple strand, in particular a double strand, formed from the at least two semi-finished products. The semi-finished products are mechanically—preferably non-detachably—connected to one another at at least one end, preferably via an end piece. In particular, it is possible that they are welded or glued to the end piece. The piece of jewelry particularly preferably has such an end piece at both ends of the semi-finished products.

It is preferably possible for the piece of jewelry to have exactly one semi-finished product wound along the first direction. According to an alternative embodiment, the piece of jewelry has exactly two semi-finished products wound parallel to one another along the first direction. According to other preferred embodiments, however, the piece of jewelry can also have a plurality of more than two semi-finished products wound parallel to one another along the first direction. In particular, the piece of jewelry can have three such semi-finished products, four such semi-finished products, five such semi-finished products, or even more than five such semi-finished products.

According to a further development of the invention, it is provided that the at least one semi-finished product of the piece of jewelry is wrapped around its circumference, that is, circumferentially, with a noble metal wire, in particular a gold wire, a platinum wire or another noble metal wire, in particular a yellow gold wire or a white gold wire. Preferably, the semi-finished product is completely wrapped with the noble metal wire along its entire longitudinal extent, in particular helically wrapped. In particular, the noble metal wire is preferably wound tightly helically around the semi-finished product, so that the semi-finished product is completely hidden by the noble metal wire, i.e. in particular completely encased. In this way, a particularly noble impression can be achieved for the piece of jewelry.

The at least two semi-finished products of the piece of jewelry are preferably each wrapped around the circumference with a noble metal wire.

The piece of jewelry preferably has a socket for at least one gemstone at at least one end. In particular, the at least one end piece is preferably designed as such a setting for a gemstone or a plurality of gemstones. The piece of jewelry preferably has such a setting for at least one gemstone, in particular as an end piece, at both ends of the at least one semi-finished product.

According to a development of the invention, it is provided that the piece of jewelry is designed as a bracelet. Due to its elastic design, the piece of jewelry can be placed around an arm, in particular the forearm, in particular near the wrist, in a particularly simple and elegant manner

The object is also achieved in that a method for producing a semi-finished product according to the invention or a semi-finished product according to one of the embodiments described above is created. The method consists of the following steps: a sheet metal, elongated in a first direction, made of an alloy according to the invention or an alloy according to one of the embodiments described above is provided. The sheet metal is formed into a slotted tube. The slotted tube is cured at a specific curing temperature for a specific curing time. The specific curing temperature ranges from at least 100° C. to at most 400° C., preferably from at least 250° C. to at most 300° C., preferably from at least 270° C. to at most 290° C., preferably 270° C., preferably 275° C., preferably 280° C., preferably 285° C., preferably 290° C. The specific curing time ranges from at least 2 hours to at most 8 hours, preferably from at least 3 hours to at most 7 hours, preferably from at least 4 hours to at most 6 hours, preferably 2 hours, preferably 2.5 hours, preferably 3 hours, preferably 3.5 hours, preferably 4 hours, preferably 4.5 hours, preferably 5 hours, preferably 5.5 hours, preferably 6 hours.

The curing temperature is preferably 270° C. and the curing time is 6 hours. The curing temperature is preferably 280° C. and the curing time is 4 hours. The curing temperature is preferably 285° C. and the curing time is 3.5 hours. The curing temperature is preferably 290° C. and the curing time is 3 hours. The curing temperature is preferably 300° C. and the curing time is 2.5 hours.

By providing the elongated sheet metal, reshaping the sheet metal into the slotted tube, and finally curing the slotted tube, the semi-finished product is ultimately obtained.

The sheet metal is provided in particular by casting the molten alloy and then rolling.

In particular, the sheet metal is formed into the slotted tube by being drawn through a round drawing die.

In the scope of the method, a semi-finished product made of a gold-containing alloy or gold alloy with elastic properties can advantageously be obtained.

According to a further development of the invention, it is provided that the semi-finished product is wound up helically along the first direction. In particular, a piece of jewelry is obtained in this way. Preferably at least two, preferably exactly two or even more than two semi-finished products wound helically along the first direction are arranged next to one another, in particular running parallel to one another, and the piece of jewelry is obtained in this way.

According to a further development of the invention, it is provided that the semi-finished product is wrapped around its circumference, i.e. circumferentially, with a noble metal wire, in particular gold wire or platinum wire, or another noble metal wire, in particular yellow gold wire or white gold wire.

Preferably, at least two parallel semi-finished products are wrapped with a precious metal wire.

Alternatively, the semi-finished products are preferably circumferentially wrapped separately from one another with the noble metal wire. The semi-finished products are then wound up helically parallel to one another.

The at least two semi-finished products wound parallel to one another are preferably mechanically connected to one another at at least one end, in particular via an end piece, preferably via a setting for at least one gemstone. Preferably, the semi-finished products are connected to one another at both ends with an end piece, in particular a socket for at least one gemstone.

In particular in this way a piece of jewelry, preferably a bracelet, is obtained.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is explained in greater detail below with reference to the drawing. In the drawings:

FIG. 1 is a schematic cross-sectional view of an embodiment of a semi-finished product, and

FIG. 2 is an embodiment of a piece of jewelry.

DETAILED DESCRIPTION

FIG. 1 is a schematic cross-sectional illustration of an embodiment of a semi-finished product 1.

The semi-finished product has the shape of a slotted tube 2 which extends along a longitudinal direction which is perpendicular to the plane of the drawing in FIG. 1. The longitudinal direction is also referred to as the first direction. The semi-finished product 1 is formed from a sheet metal 3 elongated in the first direction or longitudinal direction, which is formed so as to be circular in a second direction which is perpendicular to the first direction, in particular in the shape of a segment of a circle, preferably by drawing the sheet 3 through a round drawing die.

The semi-finished product consists of an alloy. The alloy consists in particular of at least 33 wt. %

to at most 75.5 wt. % gold, 1.5 wt. % to at most 45 wt. % silver, from at least 8 wt. % to at most 45 wt. % copper, the remainder being zinc.

The copper content of the alloy is preferably from at least 9 wt. % to at most 42 wt. %, preferably from at least 17 wt. % to at most 27 wt. %.

The silver content of the alloy is preferably from at least 2.5 wt. % to at most 39 wt. %, preferably from at least 3.5 wt. % to at most 27.5 wt. %.

The semi-finished product 1 preferably has an outside diameter D1 which is at least 0.3 mm to at most 5.0 mm An inside diameter D2 of the semi-finished product 1 is preferably from at least 0.03 mm to at most 4.5 mm. The smallest distance A in the region of the slot of the semi-finished product 1 is preferably from at least 0.02 mm to at most 1.0 mm.

The semi-finished product 1 preferably has a spring constant from at least 1500 N/m to at most 2200 N/m, preferably from at least 1600 N/m to at most 2100 N/m, measured perpendicular to the longitudinal extension, in particular measured at a distance of 15 mm from a clamping, preferably from at least 1700 N/m to at most 2050 N/m.

The semi-finished product 1 is preferably produced by providing the elongated sheet metal 3 made from the alloy, in particular by casting and rolling. The sheet metal is then formed into the slotted tube 2, in particular by drawing it through a round drawing die. The slotted tube 2 is then preferably cured at a curing temperature from at least 100° C. to at most 400° C. for a curing time from at least 2 hours to at most 8 hours. In this way, the semi-finished product 1 is finally obtained.

The semi-finished product 1 is preferably wound up helically, in particular in order to obtain a piece of jewelry. The semi-finished product 1 is preferably wrapped in the circumferential direction, in FIG. 1 in the direction of an arrow P or in the opposite direction, with a noble metal wire, in particular gold wire or platinum wire, or another noble metal wire, in particular yellow gold wire or white gold wire.

FIG. 2 shows an illustration of an embodiment of a piece of jewelry 5, the piece of jewelry 5 having at least one semi-finished product 1 according to FIG. 1 wound at least in regions along the first direction. In particular, the piece of jewelry 5 has in this case two such semi-finished products 1, which are wound up parallel to one another along the respective longitudinal direction. In particular, the semi-finished products 1 are wound up helically to form a double strand. In other embodiments, however, the piece of jewelry 5 can also have precisely one semi-finished product 1 wound up along the first direction, or more than two semi-finished products 1 wound parallel next to one another along the respective longitudinal direction.

In FIG. 2, it can also be seen that the semi-finished products 1 are each wrapped around the circumference with a noble metal wire 7, so that the actual semi-finished products 1 are no longer visible to the observer.

At least one end of the semi-finished products 1 is an end piece 9, preferably in a manner not shown in the form of a setting for at least one gemstone. In particular, the two semi-finished products 1 are mechanically connected to the end piece 9, preferably welded or glued.

In a preferred embodiment, each of the semi-finished products 1 has such an end piece 9 at both ends.

The piece of jewelry 5 is designed in particular as a bracelet 11. 

1. An alloy, comprising: 33 wt. % to 75.5 wt. % gold, 1.5 wt. % to 45 wt. % silver, 8 wt. % to 45 wt. % copper, and zinc.
 2. The alloy of claim 1, wherein the alloy has a copper content from at least 9 wt. % to at most 42 wt. %, preferably from at least 17 wt. % to at most 27 wt. %.
 3. The alloy of claim 1, wherein the alloy has a silver content from at least 2.5 wt. % to at most 39 wt. %, preferably from at least 3.5 wt. % to at most 27.5 wt. %.
 4. A semi-finished product (1) in the form of a slotted tube (2), comprising an alloy of claim
 1. 5. The semi-finished product (1) of claim 4, wherein the semi-finished product (1) is formed from a sheet metal (3) elongated in a first direction, which is shaped in a circular shape, in particular a circular segment shape, in a second direction perpendicular to the first direction.
 6. The semi-finished product (1) of claim 4, wherein the semi-finished product (1) has a spring constant, in particular measured at a distance of 15 mm from a clamping, from at least 1500 N/m to at most 2200 N/m, preferably from at least 1600 N/m to at most 2100 N/m, preferably from at least 1700 N/m to at most 2050 N/m.
 7. A piece of jewelry (5), comprising at least one semi-finished product (1) of claim 4, which is wound at least partially along a longitudinal direction.
 8. The piece of jewelry (5) of claim 7, wherein the piece of jewelry (5) has at least two semi-finished products (1) wound parallel to one another along the respective longitudinal direction.
 9. The piece of jewelry (5) of claim 7, wherein the at least one semi-finished product (1) of the piece of jewelry (5) is wrapped around its periphery with a noble metal wire (7).
 10. The piece of jewelry (5) of claim 7, wherein the piece of jewelry (5) is designed as a bracelet (11).
 11. A method for producing a semi-finished product (1), comprising: providing a sheet metal (3) elongated in a first direction made of an alloy of claim 1; forming the sheet metal (3) into a slotted tube (2); curing the slotted tube (2) at a specific curing temperature of at least 100° C. to at most 400° C. for a specific curing time from at least 2 hours to at most 8 hours, and receiving the semi-finished product (1).
 12. The method of claim 11, wherein the semi-finished product (1) is wound up helically along the first direction.
 13. The method of claim 11, wherein the semi-finished product (1) is wrapped around its circumference with a noble metal wire (7). 